The drug was first illicitly synthesised by a graduate student named Barry Kidston. Kidston had apparently studied a 1947 paper by Albert Ziering.[1] By reversing the ester of the meperidine skeleton, a drug approaching the potency of morphine was produced. However, the intermediate tertiary alcohol is liable to dehydration in acidic conditions if the reaction temperature rises above -30°C, and since Kidston did not realise this and esterified the intermediate with propanoic anhydride at room temperature, MPTP was formed as a major impurity.[2]

1-methyl-4-phenylpyridinium (MPP+), a metabolite of MPTP, causes rapid onset of irreversible symptoms similar to Parkinson's Disease.[3][4]MPTP is metabolized to the neurotoxin MPP+ by the enzyme MAO-B, which is expressed in neurons. This selectively kills brain tissue in the area of the brain called the substantia nigra and causes Parkinsonian symptoms.[5]